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如何在Android中使用Observer監(jiān)聽網(wǎng)絡(luò)狀態(tài)?針對(duì)這個(gè)問題,這篇文章詳細(xì)介紹了相對(duì)應(yīng)的分析和解答,希望可以幫助更多想解決這個(gè)問題的小伙伴找到更簡(jiǎn)單易行的方法。
觀察者模式屬于面向?qū)ο蟮?3中設(shè)計(jì)模式之一,不了解的同學(xué)請(qǐng)自行Google
既然用觀察者模式,自然離不開觀察者模式里最重要的兩個(gè)類Subject和Ovserver了
Subjcet接口:
/** * Description: observer subject * author: Wang * date: 11/28/16 11:19 AM * * Copyright©2016 by wang. All rights reserved. */ public interface NetConnectionSubject { /** * 注冊(cè)觀察者 * * @param observer */ public void addNetObserver(NetConnectionObserver observer); /** * 移除觀察者 * * @param observer */ public void removeNetObserver(NetConnectionObserver observer); /** * 狀態(tài)更新通知 * * @param type */ public void notifyNetObserver(int type); }
Observer接口:
/** * Description: observer * author: Wang * date: 11/28/16 11:20 AM * * Copyright©2016 by wang. All rights reserved. */ public interface NetConnectionObserver { /** * 通知觀察者更改狀態(tài) * * @param type */ public void updateNetStatus(int type); }
在Android里,最適合實(shí)現(xiàn)Subject類的,莫過(guò)于Application了,因?yàn)樗治ㄒ欢疑芷诰褪沁@個(gè)App的生命周期:
/** * Description: App's application should extend this class * author: Wang * date: 11/28/16 10:34 AM * * Copyright©2016 by wang. All rights reserved. */ public abstract class BaseApplication extends Application implements NetConnectionSubject { protected static BaseApplication instance; private int currentNetType = -1; private List<NetConnectionObserver> observers = new ArrayList<>(); public static BaseApplication getInstance() { return instance; } /** * current net connection type * * @return */ public int getCurrentNetType() { return currentNetType; } /** * current net connection status * * @return */ public boolean isNetConnection() { return currentNetType == NetWorkUtil.NET_NO_CONNECTION ? false : true; } @Override public void onCreate() { super.onCreate(); instance = this; currentNetType = NetWorkUtil.getConnectionType(this); } @Override public void addNetObserver(NetConnectionObserver observer) { if (!observers.contains(observer)) { observers.add(observer); } } @Override public void removeNetObserver(NetConnectionObserver observer) { if (observers != null && observers.contains(observer)) { observers.remove(observer); } } @Override public void notifyNetObserver(int type) { /** * 避免多次發(fā)送相同的網(wǎng)絡(luò)狀態(tài) */ if (currentNetType == type) { return; } else { currentNetType = type; if (observers != null && observers.size() > 0) { for (NetConnectionObserver observer : observers) { observer.updateNetStatus(type); } } } } }
具體誰(shuí)要實(shí)現(xiàn)Observer接口,就要看具體場(chǎng)景了,這里以Activity為栗子吧:
/** * Description: TODO * author: WangKunHui * date: 16/12/30 下午3:08 * <p> * Copyright©2016 by wang. All rights reserved. */ public class TestActivity extends Activity implements NetConnectionObserver { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); /**省略一些方法**/ BaseApplication.getInstance().addNetObserver(this); } @Override public void updateNetStatus(int type) { //當(dāng)監(jiān)聽網(wǎng)絡(luò)狀態(tài)發(fā)生變化 這里會(huì)及時(shí)的收到回饋 } @Override protected void onDestroy() { super.onDestroy(); BaseApplication.getInstance().removeNetObserver(this); } }
這里有個(gè)地方一定要注意:當(dāng)Activity銷毀的時(shí)候,一定要把這個(gè)觀察者從觀察者隊(duì)列里移除掉!否者會(huì)發(fā)生內(nèi)存泄漏
到這里,觀察者模式已經(jīng)寫完了,謝謝收看。
讀者:你是不是忘了點(diǎn)什么,說(shuō)好的網(wǎng)絡(luò)監(jiān)聽呢?
我:Easy easy~ 剛剛只不過(guò)是中場(chǎng)休息
如果只有上面那么多的話,是不能監(jiān)聽網(wǎng)絡(luò)狀態(tài)的,想要監(jiān)聽網(wǎng)絡(luò)狀態(tài)的變化,還得靠我們的廣播接收者啊,有請(qǐng):
/** * Description: 網(wǎng)絡(luò)連接狀態(tài)的監(jiān)聽 * author: Wang * date: 16/8/3 下午10:54 * * Copyright©2016 by wang. All rights reserved. */ public class NetConnectionReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { if (intent.getAction().equals(ConnectivityManager.CONNECTIVITY_ACTION)) { int connectionType = NetWorkUtil.getConnectionType(context); /** * 更改網(wǎng)絡(luò)狀態(tài) */ if (BaseApplication.getInstance() != null) { BaseApplication.getInstance().notifyNetObserver(connectionType); } } } }
NetWorkUtil:
/** * @author Wang * @version 1.0.0 * @description 網(wǎng)絡(luò)操作工具類 * @create 2014-2-18 上午09:22:30 * @company */ public class NetWorkUtil { /** * 無(wú)網(wǎng)絡(luò)鏈接 */ public static final int NET_NO_CONNECTION = 0; /** * wifi */ public static final int NET_TYPE_WIFI = 1; public static final int NET_TYPE_2G = 2; public static final int NET_TYPE_3G = 3; public static final int NET_TYPE_4G = 4; /** * 未知的網(wǎng)絡(luò)類型 */ public static final int NET_TYPE_UNKNOWN = 5; /** * 獲取網(wǎng)絡(luò)類型 * * @param context * @return */ public static int getConnectionType(Context context) { int netType = NET_NO_CONNECTION; NetworkInfo networkInfo = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo(); if (networkInfo == null) { netType = NET_NO_CONNECTION; } else { if (networkInfo.getType() == ConnectivityManager.TYPE_WIFI) { netType = NET_TYPE_WIFI; } else { int networkType = networkInfo.getSubtype(); switch (networkType) { case TelephonyManager.NETWORK_TYPE_GPRS: case TelephonyManager.NETWORK_TYPE_EDGE: case TelephonyManager.NETWORK_TYPE_CDMA: case TelephonyManager.NETWORK_TYPE_1xRTT: case TelephonyManager.NETWORK_TYPE_IDEN: //api<8 : replace by 11 netType = NET_TYPE_2G; break; case TelephonyManager.NETWORK_TYPE_UMTS: case TelephonyManager.NETWORK_TYPE_EVDO_0: case TelephonyManager.NETWORK_TYPE_EVDO_A: case TelephonyManager.NETWORK_TYPE_HSDPA: case TelephonyManager.NETWORK_TYPE_HSUPA: case TelephonyManager.NETWORK_TYPE_HSPA: case TelephonyManager.NETWORK_TYPE_EVDO_B: //api<9:replace by 14 case TelephonyManager.NETWORK_TYPE_EHRPD: //api<11:replace by 12 case TelephonyManager.NETWORK_TYPE_HSPAP: //api<13:replace by 15 netType = NET_TYPE_3G; break; case TelephonyManager.NETWORK_TYPE_LTE: //api<11:replace by 13 netType = NET_TYPE_4G; break; default: String subType = networkInfo.getSubtypeName(); if (subType.equalsIgnoreCase("TD-SCDMA") || subType.equalsIgnoreCase("WCDMA") || subType.equalsIgnoreCase("CDMA2000")) { netType = NET_TYPE_3G; } else { netType = NET_TYPE_UNKNOWN; } break; } } } return netType; } }
Android是一種基于Linux內(nèi)核的自由及開放源代碼的操作系統(tǒng),主要使用于移動(dòng)設(shè)備,如智能手機(jī)和平板電腦,由美國(guó)Google公司和開放手機(jī)聯(lián)盟領(lǐng)導(dǎo)及開發(fā)。
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